Health Library

Aneurysm in the brain

Aneurysm - cerebral; Cerebral aneurysm; Aneurysm - intracranial

An aneurysm is a weak area in the wall of a blood vessel that causes the blood vessel to bulge or balloon out. When an aneurysm occurs in a blood vessel of the brain, it is called a cerebral, or intracranial, aneurysm.

Causes

Aneurysms in the brain occur when there is a weakened area in the wall of a blood vessel. An aneurysm may be present from birth (congenital). Or, it may develop later in life, such as after a blood vessel is injured.

Aneurysms

An aneurysm is an abnormal widening or ballooning of a part of an artery due to weakness in the wall of the blood vessel.

There are many types of brain aneurysms. The most common type is called a berry aneurysm. This type can vary in size from a few millimeters to over a centimeter. Giant berry aneurysms can be bigger than 2.5 centimeters. These are more common in adults. Berry aneurysms are passed down through families more often than other types of aneurysms.

Other types of cerebral aneurysms involve widening of an entire blood vessel. Or, they may appear as a ballooning out of part of a blood vessel. Such aneurysms can occur in any blood vessel that supplies the brain. Hardening of arteries (atherosclerosis), trauma, and infection can all injure the blood vessel wall and cause cerebral aneurysms.

Atherosclerosis

Hardening of the arteries, also called atherosclerosis, occurs when fat, cholesterol, and other substances build up in the walls of arteries. These ...

Symptoms

A person may have an aneurysm without having any symptoms. This kind of aneurysm may be found when an MRI or CT scan of the brain is done for another reason.

A brain aneurysm may begin to leak a small amount of blood. This may cause a severe headache that a person may describe as "the worst headache of my life." It may be called a thunderclap or sentinel headache. This means the headache could be a warning sign of a future rupture that may occur days to weeks after the headache first started.

Headache

A headache is pain or discomfort in the head, scalp, or neck. Serious causes of headaches are rare. Most people with headaches can feel much better...

NOTE: A ruptured aneurysm is a medical emergency. Call your local emergency number, such as 911.

Exams and Tests

An eye exam may show signs of increased pressure in the brain, including swelling of the optic nerve or bleeding into the retina of the eye. A brain and nervous system exam may show abnormal eye movement, speech, strength, or sensation.

The following tests may be used to diagnose a cerebral aneurysm and determine the cause of bleeding in the brain:

Cerebral angiography or spiral CT scan angiography of the head to show the location and size of the aneurysm

Cerebral angiography

Cerebral angiography is a procedure that uses a special dye (contrast material) and x-rays to see how blood flows through the brain.

Brain surgery (craniotomy)

Endovascular repair is most often done. It usually involves a coil or coiling. This is a less invasive way to treat some aneurysms.

Not all aneurysms need to be treated right away. Those that are very small (less than 3 mm) are less likely to break open.

Your provider will help you decide whether or not it is safer to have surgery to block off the aneurysm before it can break open. Sometimes people are too ill to have surgery, or it may be too dangerous to treat the aneurysm because of its location.

A ruptured aneurysm is an emergency that needs to be treated right away. Treatment may involve:

Being admitted to the hospital's intensive care unit (ICU)

Complete bed rest and activity restrictions

Drainage of blood from the brain area (cerebral ventricular drainage)

Drugs to prevent seizures

Drugs to control headaches and blood pressure

Drugs through a vein (IV) to prevent infection

Once the aneurysm is repaired, treatment may be needed to prevent a stroke from a blood vessel spasm.

Outlook (Prognosis)

How well you do depends on many things. People who are in a deep coma after an aneurysm rupture do not do as well as those with less severe symptoms.

Ruptured cerebral aneurysms are often deadly. Of those who survive, very few have some sort of permanent disability.

Subarachnoid hemorrhage

When to Contact a Medical Professional

Go to the emergency room or call the local emergency number (such as 911) if you have a sudden or severe headache, especially if you also have nausea, vomiting, seizures, or any other nervous system symptom.

Also call if you have a headache that is unusual for you, especially if it is severe or your worst headache ever.

Prevention

There is no known way to prevent a berry aneurysm from forming. Treating high blood pressure may reduce the chance that an existing aneurysm will rupture. Controlling risk factors for atherosclerosis may reduce the likelihood of some types of aneurysms.

High blood pressure

Blood pressure is a measurement of the force exerted against the walls of your arteries as your heart pumps blood to your body. Hypertension is the ...

Cerebral aneurysm - illustration

An aneurysm is a sac-like protrusion of an artery caused by a weakened area within the vessel wall. If a cerebral (brain) aneurysm ruptures, the escaping blood within the brain may cause severe neurologic complications or death. A person who has a ruptured cerebral aneurysm may complain of the sudden onset of "the worst headache of my life."

Cerebral aneurysm

illustration

Cerebral aneurysm - illustration

Weakness, numbness, or other loss of nerve function may indicate that an aneurysm may be causing pressure on adjacent brain tissue. Symptoms such as a severe headache, nausea, vomiting, vision changes or other neurological changes can indicate the aneurysm has ruptured and is bleeding into the brain. A ruptured intracranial aneurysm causes intracranial bleeding and is considered very dangerous.

Cerebral aneurysm

illustration

Cerebral aneurysm - illustration

An aneurysm is a sac-like protrusion of an artery caused by a weakened area within the vessel wall. If a cerebral (brain) aneurysm ruptures, the escaping blood within the brain may cause severe neurologic complications or death. A person who has a ruptured cerebral aneurysm may complain of the sudden onset of "the worst headache of my life."

Cerebral aneurysm

illustration

Cerebral aneurysm - illustration

Weakness, numbness, or other loss of nerve function may indicate that an aneurysm may be causing pressure on adjacent brain tissue. Symptoms such as a severe headache, nausea, vomiting, vision changes or other neurological changes can indicate the aneurysm has ruptured and is bleeding into the brain. A ruptured intracranial aneurysm causes intracranial bleeding and is considered very dangerous.